Prosthetic components and methods for joint line access

ABSTRACT

A method for joint line assembly of an orthopaedic prosthesis assembly includes inserting a tapered post of a first prosthetic component into a tapered bore of a second prosthetic component along a longitudinal axis to secure the first prosthetic component to the second prosthetic component. A shaft of a fastener is advanced along the longitudinal axis through a threaded passageway defined in the second prosthetic component and into the first prosthetic component. The threaded passageway has a greater diameter than a diameter of the shaft. The end of the shaft is threaded into a threaded aperture defined in the first prosthetic component.

CROSS-REFERENCE

Cross reference is made to copending U.S. patent application Ser. No.______ entitled “PROSTHETIC COMPONENTS WITH SECONDARY RETENTION”(Attorney Docket No. 265280-223850, DEP6644USNP2); and copending U.S.patent application Ser. No. ______ entitled “INSTRUMENTS FOR USE INDISASSEMBLING IMPLANTS” (Attorney Docket No. 265280-223295,DEP6644USNP), each of which is assigned to the same assignee as thepresent application, each of which is filed concurrently herewith, andeach of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to an implantable orthopaedicprosthesis, and more particularly to an implantable knee prosthesis.

BACKGROUND

During the lifetime of a patient, it may be necessary to perform a jointreplacement procedure on the patient as a result of, for example,disease or trauma. The joint replacement procedure may involve the useof a prosthesis which is implanted into one or more of the patient'sbones. In the case of a knee replacement procedure, a tibial tray isimplanted into the patient's tibia. A bearing is secured to the tibialtray. The condyle surfaces of a replacement femoral component bearagainst the tibial bearing.

Such a knee prosthesis may also include a number of elongatedintramedullary stem components and optional prosthetic components (e.g.,sleeves and/or adaptors) which are implanted in the patient's tibiaand/or femur. To secure a stem component and/or other components to thepatient's tibia and/or femur, the intramedullary canal of the patient'stibia and/or femur is first surgically prepared (e.g., reamed) such thatthe stem component and/or other components may be subsequently implantedtherein. In some designs, the stem component is implanted in thepatient's bone by use of cementless fixation. One type of such a designis known as a ‘press fit’ stem component.

Various orthopaedic surgical instruments are used throughout such anorthopaedic procedure. For example, bone saws and/or reamers may be useto surgically prepare a bone surface to accept an orthopaedic implant.Additionally, depending on the particularly implant, a variety oforthopaedic surgical instruments may be used to assembly, disassembly,and/or install the orthopaedic implant into the prepared bone.

SUMMARY

According to one aspect of the disclosure, an orthopaedic surgicalinstrument is disclosed. The orthopaedic surgical instrument includes amain component, a rod component, and a spindle component. The spindlecomponent includes a housing and an elongated body extending from thehousing. The housing and the elongated body define a longitudinal axisand a passageway is defined in the elongated body along the longitudinalaxis. The rod component includes a head configured to be received in thehousing of the main component and an elongated shaft extending from thehead. The elongated shaft is configured to pass through the elongatedbody of the main component and has a length greater than a length of theelongated body of the main component. The spindle component includes athreaded body configured to thread into the housing to move the rodcomponent along the longitudinal axis.

In some embodiments, the rod component may be selected from a pluralityof rod components with each rod component of the plurality of rodcomponents having an elongated shaft with a different length. An end ofthe elongated body of the main component opposite the housing may have athreaded outer surface. Additionally, the head of the rod component mayhave a diameter greater than a diameter of the passageway of theelongated body of the main component.

In some embodiments, the spindle component may include an aperturedefined at an end of the threaded body, the aperture may be sized to fitthe head of the rod component. Further, the diameter of the aperture maybe less than a diameter of the spindle component. The spindle componentmay include a handle body opposite the threaded body configured toreceive a handle component for threading the spindle component. An outersurface of the housing of the main component may be shaped to match aconnection surface of a wrench component. Additionally, the outersurface may be shaped to match a connection surface of a hex wrench.

According to another aspect, a method for disassembling a femoralcomponent assembly is disclosed. The method includes securing an end ofa main component to a femoral component, advancing a rod in a firstdirection through the main component and into contact with a stemcomponent secured to the femoral component and positioned in a bone of apatient, threading a spindle component into the main component to applya force in the first direction to the rod, and continuing to thread thespindle component into the main component to increase the force appliedin the first direction to disengage the femoral component from the stemcomponent.

In some embodiments, the method may include removing a fastener securingthe femoral component to the stem component from the femoral componentassembly. Additionally, the method may include engaging a fastener witha driver positioned along a joint line, unthreading the fastener fromthe stem component using the driver, and removing the fastener from thefemoral component assembly.

In some embodiments, the method may include removing a retention devicefrom a threaded passageway of the stem post of the femoral component,such that the retention device is configured to prevent an end of thefastener from reentering the threaded passageway after being secured tothe stem component. Removing the retention device may include driving aremoval screw into the retention device. Additionally, the end of themain component to the femoral component may include threading anelongated body of the main component into a threaded passageway definedin the femoral component. Further, continuing to thread the spindlecomponent may include continuing to thread the spindle component intothe main component to increase the force applied in the first directionto move the femoral component in a second direction opposite the firstdirection.

According to another aspect, a method for disassembling an orthopaedicprosthesis assembly is disclosed. The method may include securing an endof a first surgical instrument to a first prosthetic component,advancing a rod in a first direction through the first prostheticcomponent and into contact with a second prosthetic component secured tothe first prosthetic component, threading a second surgical instrumentinto the first surgical instrument to apply a force in the firstdirection to the rod, and continuing to thread the second surgicalinstrument into the first surgical instrument to increase the forceapplied in the first direction to the rod to disengage the firstprosthetic component from the second prosthetic component.

In some embodiments, the method may include removing a fastener securingthe first prosthetic component to the second prosthetic component andremoving a retention device from a threaded passageway of the firstprosthetic component, the retention device configured to prevent an endof the fastener from reentering the threaded passageway after beingsecured to the second prosthetic component. Further, securing the end ofthe first surgical instrument to the first prosthetic component mayinclude threading an elongated body of the first surgical instrumentinto a threaded passageway defined in the first prosthetic component.Additionally, continuing to thread the second surgical instrument mayinclude continuing to thread the second surgical instrument into thefirst surgical instrument to increase the force applied in the firstdirection to move the first prosthetic component in a second directionopposite the first direction.

According to another aspect of the disclosure, an implantableorthopaedic knee prosthesis assembly is disclosed. The implantableorthopaedic knee prosthesis assembly includes a femoral componentconfigured to be implanted into a distal end of a femur of a patient, astem component including a tapered post configured to be received in thetapered bore of the femoral component, a fastener, and a retentiondevice. The femoral component includes a bearing surface having a medialcondyle surface and a lateral condyle surface, a backside surfaceopposite the bearing surface, and a stem post extending superiorly awayfrom the backside surface along an axis. The stem post has a proximaltapered bore, a distal passageway, and a threaded passageway connectingthe proximal tapered bore and the distal passageway. The tapered postincludes a bore formed therein extending proximally along the axis and athreaded aperture defined at a proximal end of the bore. The fastenerincludes a head configured to be received in the distal passageway andan elongated shaft having a proximal end configured to be positioned inthe threaded aperture. Additionally, the retention device is configuredto be received in the threaded passageway to prevent the proximal end ofthe fastener from entering the threaded passageway. Further, the head ofthe fastener has a diameter larger than a diameter of the threadedpassageway and the elongated shaft has a diameter less than the diameterof the threaded passageway.

In some embodiments, the stem component may include an elongated bodyextending from the tapered post along the axis. The proximal end of theelongated shaft of the fastener may include a threaded portion to bethreaded into the threaded aperture of the stem component. Additionally,a distance the fastener is configured to move with the retention devicereceived in the threaded passageway may be a function of a length of thethreaded portion. Further, the retention device may be composed ofpolymeric material.

According to another aspect, an orthopaedic prosthesis assembly includesa first prosthetic component, a second prosthetic component, a fastener,and a retention device. The first prosthetic component is configured tobe implanted into a bone of a patient and includes a surface configuredto contact the bone and a stem post extending away from the surfacealong an axis. The stem post has a tapered bore, a first passageway, anda threaded second passageway connecting the tapered bore and the firstpassageway. The second prosthetic component includes a tapered postreceived in the tapered bore of the first prosthetic component. Further,the tapered post has a bore formed therein extending along the axis anda threaded aperture defined at an end of the bore. The fastener includesa head received in the first passageway and an elongated body extendingthrough the threaded second passageway along the axis and having an endpositioned in the threaded aperture. Additionally, the retention deviceis received in the stem post to prevent the end of the fastener fromentering the first passageway.

In some embodiments, the first prosthetic component may be a femoralcomponent. In another embodiment, the first prosthetic component may bea tibial tray. The second prosthetic component may a stem component.Additionally, the head of the fastener may have a diameter greater thana diameter of the threaded second passageway and the elongated body ofthe fastener may have a diameter less than the diameter of the threadedsecond passageway. The end of the elongated body of the fastener may bethreaded into the threaded aperture of the second prosthetic component.

In some embodiment, the elongated body of the fastener may be configuredto pass through the retention device, and the retention device may bereceived in the threaded second passageway of the first prostheticcomponent. The retention device may be received in the first passageway.Additionally, the retention device may include polymeric material.Further, the retention device may include high molecular weightpolyethylene.

According to another aspect, a method for assembling an implantableorthopaedic knee prosthesis assembly includes inserting a post of a stemcomponent into a bore defined in a femoral component to secure the stemcomponent to the femoral component, advancing an end of a fastenerthrough a threaded passageway defined in the femoral component and intothe post of the stem component, threading the end of the fastener into athreaded aperture defined in the stem component, and engaging aretention device with the femoral component to prevent the end of thefastener from reentering the threaded passageway after advancing the endof the fastener through the threaded passageway and into the post of thestem component.

In some embodiments, inserting the post of the stem component into thebore may include inserting a tapered post of a stem component into atapered bore defined in a femoral component to secure to the stemcomponent to the femoral component. Additionally, the method may includeinserting the assembled implantable orthopaedic knee prosthesis assemblyinto a prepared bone of a patient.

In some embodiments, engaging the retention device with the femoralcomponent may include engaging a retention device with the threadedpassageway of the femoral component to prevent the end of the fastenerfrom reentering the threaded passageway after advancing the end of thefastener through the threaded passageway and into the post of the stemcomponent. Additionally, engaging the retention device with the femoralcomponent may include inserting a retention device into a passageway ofthe femoral component distal to the threaded passageway to prevent theend of the fastener from reentering the threaded passageway afteradvancing the end of the fastener through the threaded passageway andinto the post of the stem component.

According to another aspect of this disclosure, a method for joint lineassembly of an orthopaedic prosthesis assembly includes inserting atapered post of a first prosthetic component into a tapered bore of asecond prosthetic component along a longitudinal axis to secure thefirst prosthetic component to the second prosthetic component, advancingalong the longitudinal axis a shaft of a fastener through a threadedpassageway defined in the second prosthetic component and into the firstprosthetic component such that the threaded passageway has a greaterdiameter than a diameter of the shaft, and threading an end of the shaftinto a threaded aperture defined in the first prosthetic component.

In some embodiments, the first prosthetic component may be a stemcomponent and the second prosthetic component may be a femoral componentthat may include a bearing surface having a medial condyle surface and alateral condyle surface, a backside surface opposite the bearingsurface, and a stem post extending superiorly away from the backsidesurface, the tapered bore being defined in the stem post. The secondprosthetic component may be a femoral sleeve component including aplurality of step surfaces and the first prosthetic component may be astem component including an elongated body extending from the taperedpost.

In some embodiments, the method may include inserting a tapered stempost of a femoral component into a second tapered bore of the secondprosthetic component to secure the femoral component to the secondprosthetic component. The femoral component may include a bearingsurface having a medial condyle surface and a lateral condyle surface, abackside surface opposite the bearing surface, and the tapered stem postextending superiorly away from the backside surface, and the firstsecond prosthetic component may be a femoral sleeve component includinga plurality of step surfaces and the first prosthetic component may be astem component including an elongated body extending from the taperedpost.

In some embodiments, the first prosthetic component may be a stemcomponent including an elongated body extending from the tapered postand the second prosthetic component may be a tibial tray including abearing surface configured to contact a bearing a backside surfaceopposite the bearing surface, and a stem post extending inferiorly awayfrom the backside surface such that the tapered bore is defined in thestem post. Inserting the tapered post of the first prosthetic componentinto the tapered bore of the second prosthetic component may includesecuring the first prosthetic component to the second prostheticcomponent by a taper fit. Additionally, the first prosthetic componentmay be secured to the second prosthetic component by only the taper fitand the fastener. Further, the method may include advancing a retentiondevice through the second prosthetic component along the longitudinalaxis to engage the threaded passageway defined in the second prostheticcomponent.

According to another aspect, a method for joint line assembly of anorthopaedic prosthesis assembly may include inserting a tapered post ofa stem component into a first tapered bore of a femoral sleeve componentalong a longitudinal axis to secure the stem component to the femoralsleeve component such that the first tapered bore is located at a firstend of the femoral sleeve component, advancing along the longitudinalaxis a shaft of a fastener through a threaded passageway defined in thefemoral sleeve component and into the stem component such that the shafthas a first diameter and the threaded passageway has a second diametergreater than the first diameter, threading the end of the fastener intoa threaded aperture defined in the stem component, and inserting atapered stem post of a femoral component into a second tapered bore ofthe femoral sleeve component along the longitudinal axis to secure thefemoral component to the femoral sleeve component such that the secondtapered bore is located at a second end of the femoral sleeve componentopposite the first end along the longitudinal axis.

In some embodiments, the stem component and the femoral sleeve componentmay be secured by only a taper fit between the stem component and thefemoral component and the fastener. Additionally, the method may includeinserting the stem component into a femur of a patient. Advancing theshaft of a fastener may include advancing a head of the fastener througha distal passageway defined in the femoral sleeve component distal tothe threaded passageway, the head having a third diameter greater thanthe second diameter.

In some embodiment, advancing the end of the fastener through thethreaded passageway may include advancing the end of the fastenerthrough the threaded passageway defined in the femoral sleeve componentprior to inserting the tapered stem post of the femoral component intothe second tapered bore of the femoral sleeve component. The method mayinclude advancing a retention device through the femoral sleevecomponent along the longitudinal axis to engage the threaded passagewaydefined in the femoral sleeve component.

According to another aspect of this disclosure, an orthopaedicprosthesis assembly is disclosed. The orthopaedic prosthesis assemblyincludes a first prosthetic component, a second prosthetic component,and a third prosthetic component. The first prosthetic componentincludes an outer surface, a surface positioned opposite the outersurface that is configured to contact a bone of a patient and a stempost extending from the surface along an axis. The second prostheticcomponent includes a first end secured to stem post of the firstprosthetic component, a second end opposite the first end, and a taperedbore defined in the second end. The third prosthetic component includesa tapered post received in the tapered bore of the second prostheticcomponent. Further, the tapered post has a bore formed therein extendingalong the axis. Additionally, a passageway is defined in the orthopaedicknee prosthesis assembly along the axis from the outer surface of thefirst prosthetic component to an end of the bore of the third prostheticcomponent. A fastener extends along the axis is secured to the secondprosthetic component and the third prosthetic component.

In some embodiments, each of the first prosthetic component, the secondprosthetic component, and the third prosthetic component is devoid of anopening transverse to the axis. Additionally, the second prostheticcomponent may be a femoral sleeve component including a plurality ofstep surfaces and the third prosthetic component may be a stem componentincluding an elongated body extending from the tapered post.

In some embodiments, the first prosthetic component may be a femoralcomponent and may include the outer surface having a medial condylesurface and a lateral condyle surface, a backside surface opposite thebearing surface, and a tapered stem post extending superiorly away fromthe backside surface. In another embodiment, the first prostheticcomponent may be a tibial tray including the outer surface, which isconfigured to contact a bearing a backside surface opposite outersurface, and the stem post extending inferiorly away from the backsidesurface. In such an embodiment, the second prosthetic component may atibial stem adaptor including a second tapered post defined at the firstend and the third prosthetic component may be a stem component having anelongated body extending from the tapered post.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a perspective view of an implantable orthopaedic kneeprosthesis assembly;

FIG. 2 is an exploded perspective view of a femoral component assemblyof the implantable orthopaedic knee prosthesis assembly of FIG. 1;

FIG. 3 is a cross sectional view of the femoral component assembly ofFIG. 2;

FIG. 4 is an exploded perspective view of a tibial component assembly ofthe implantable orthopaedic knee prosthesis assembly of FIG. 1;

FIG. 5 is a cross sectional view of the tibial component assembly ofFIG. 4;

FIG. 6 is an exploded perspective view of a femoral component assemblyincluding a femoral sleeve;

FIG. 7 is a cross sectional view of the femoral component assembly ofFIG. 6;

FIG. 8 is an exploded perspective view of a tibial component assemblyincluding a tibial sleeve;

FIG. 9 is an exploded perspective view of a disassembly tool;

FIG. 9A is a fragmentary cross sectional view of a main component of thedisassembly tool of FIG. 9 taken along the line 9A-9A in FIG. 9;

FIGS. 10-15 show the disassembly tool of FIG. 9 used in an orthopaedicsurgical procedure with the femoral component assembly of FIGS. 1-3;

FIGS. 16-18 show the disassembly tool of FIG. 9 used in an orthopaedicsurgical procedure with the tibial component assembly of FIG. 8;

FIG. 19 shows a cross sectional view of another embodiment of theretention device;

FIG. 20 shows a cross sectional view of another embodiment of theretention device; and

FIG. 21 shows a perspective view of the retention device of FIG. 20.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthis disclosure in reference to both the orthopaedic implants describedherein and a patient's natural anatomy. Such terms have well-understoodmeanings in both the study of anatomy and the field of orthopaedics. Useof such anatomical reference terms in the specification and claims isintended to be consistent with their well-understood meanings unlessnoted otherwise.

Referring now to FIG. 1, there is shown an implantable orthopaedic kneeprosthesis assembly 10 for use in the performance of an orthopaedic kneereplacement procedure. The knee prosthesis assembly 10 includes afemoral component 12, a tibial tray 14, and a bearing 16. The kneeprosthesis assembly 10 also includes a stem component 18 secured to thefemoral component 12 and a stem component 18 secured to the tibial tray14.

The tibial tray 14 is configured to be implanted into asurgically-prepared end of a patient's proximal tibia (not shown). Thetibial tray 14 includes a platform 20 having an elongated stem post 22extending inferiorly away from its inferior surface 24. The elongatedtibial stem post 22 is configured to receive the stem component 18.Specifically, the stem post 22 of the tibial tray 14 has a tapered bore26 (see FIG. 5) formed therein into which a tapered post 28 of the stemcomponent 18 may be advanced to taper lock the post 28 (and hence thestem component 18) and the tibial tray 14 to one another. In such a way,the stem component 18 may then be implanted into a surgically-prepared(e.g., reamed or broached) intramedullary canal of the patient's tibia.Further, as discussed in detail below, the tibial tray 14 and the stemcomponent 18 each have threaded passages for use with a disassemblytool.

The bearing 16 is securable to the tibial tray 14. In particular, thebearing 16 may be snap-fit to the tibial tray 14. In such a way, thebearing 16 is fixed relative to the tibial tray 14 (i.e., it is notrotatable or moveable in the anterior/posterior or medial/lateraldirections). Although, in other embodiments, the bearing 16 may besecured in a manner that allows it to rotate relative to the tibial tray14.

The bearing 16 includes a lateral bearing surface 30 and a medialbearing surface 32. The bearing surfaces 30, 32 are configured toarticulate with a lateral condyle surface 34 and a medial condylesurface 36, respectively, of the femoral component 12. Specifically, thefemoral component 12 is configured to be implanted into asurgically-prepared distal end of the patient's femur (not shown), andis configured to emulate the configuration of the patient's naturalfemoral condyles. As such, the lateral condyle surface 34 and the medialcondyle surface 36 are configured (e.g., curved) in a manner whichmimics the condyles of the natural femur. The lateral condyle surface 34and the medial condyle surface 36 are spaced apart from one anotherthereby defining an intercondylar notch 38 therebetween.

The condyle surfaces 34, 36 are formed in a bearing surface 40 of thefemoral component 12. The femoral component 12 also includes anelongated stem post 42, extending superiorly away from its oppositebackside surface 44. The elongated femoral stem post 42 is configured toreceive the stem component 18. Specifically, the femoral component 12has a tapered bore 46 formed therein into which a tapered post 28 of thestem component 18 may be advanced to taper lock the post 28 (and hencethe stem component 18) and the femoral component 12 to one another (asshown in FIG. 1). In such a way, the stem component 18 may then beimplanted into a surgically-prepared (e.g., reamed or broached)intramedullary canal of the patient's femur. Additionally, the femoralcomponent 12 and the stem component 18 each have threaded passagewaysfor use with the disassembly tool 208.

As shown in FIG. 1, each of the stem components 18 includes anelongated, generally cylindrical stem body 48. The tapered post 28 ispositioned at a proximal end of the elongated stem body 48. Theelongated stem body 48 extends distally away from the tapered post 28and terminates at rounded distal end 50 that defines the inferior-mostsurface of the stem component 18 when it is secured to a tibial tray 14or the superior-most surface of the stem component 18 when it is securedto a femoral component 12. As can be seen in FIG. 1, a number ofelongated flutes 52 are formed in the outer annularly-shaped surface 54of the stem body 48. The longitudinal axis of each of the flutes 52 isparallel to the longitudinal axis of the stem component 18 and hence isarranged in the superior/inferior direction.

The stem component 18 may be provided in a number of differentconfigurations in order to fit the needs of a given patient's anatomy.In particular, the stem component 18 may be configured in variousdifferent lengths to conform to the patient's anatomy (e.g., arelatively long stem component 18 for use with a long femur or tibia, arelatively short stem component 18 for use with a short femur or tibia,etcetera). The stem component 18 may also be provided in varying bodydiameters to fit the needs of a given patient's anatomy. The bodydiameter of a given stem component 18 is the stem component'smedial/lateral cross sectional width in the cylindrical midsection ofthe stem component's body (i.e., not at its tapered post or its distaltip). In other embodiments, the stem component 18 may have some othershape (e.g., non-cylindrical) and size. Likewise, the femoral component12 and the tibial tray may 14 be provided in various different sizes tofit the needs of a given patient's anatomy.

As described below, the knee prosthesis assembly 10 may also include anumber of optional components in various embodiments. For example, theknee prosthesis assembly 10 may include a femoral sleeve component 56, atibial sleeve component 58, and a stem adaptor 60. The sleeve components56, 58 may be used to facilitate implantation of the femoral component12 and the tibial tray 14, respectively, in the presence of reduced bonequality in the patient's femur or tibia. The femoral sleeve component 56is configured to be secured to the femoral component 12 so as to bepositioned between the femoral component 12 and the stem component 18.In particular, the inferior end 62 of the femoral sleeve component 56has a bore 180 formed therein that may be taper locked to the outersurface 182 of the femoral component's stem post 42 to lock the sleevecomponent 56 to the femoral component 12. The opposite, superior end ofthe femoral sleeve component 56 is configured to receive the stemcomponents 18. Specifically, the superior end of the femoral sleevecomponent 56 has a tapered bore 64 formed therein into which a taperedpost 28 of one of the stem components 18 may be advanced to taper lockthe post 28 (and hence the stem component 18) and the femoral sleevecomponent 56 to one another.

The tibial sleeve component 58 may be embodied in a similar manner inwhich a bore formed in its superior end is taper locked to the stem post22 of the tibial tray 14, with its opposite, inferior end having atapered bore formed therein into which a tapered post 28 of one of thestem components 18 may be advanced to taper lock the post 28 (and hencethe stem component 18) and the tibial sleeve component 58 to oneanother.

Alternatively, as shown in FIG. 1, the tibial sleeve component 56 may beused in conjunction with the stem adaptor 60. In such an embodiment, thestem adaptor 60 is used to secure both the stem components 18 and thetibial sleeve component 58 to the tibial tray 14. In particular, thestem adaptor 60 includes a tapered post 66 that is identical in shapeand size to the tapered post 28 of each of the stem components 158. Assuch, the tapered post 66 of the stem adaptor 60 may be advanced intothe tapered bore 26 formed in the tibial tray's stem post 22 to taperlock the post 22 (and hence the stem adaptor 60) and the tibial tray 14to one another. The tibial sleeve component 58 is configured to besecured to the stem adaptor 60 so as to be positioned between the tibialtray 14 and the stem component 18. In particular, the tibial sleevecomponent 58 has a bore 68 formed therein that extends through itsentire length and hence is open to both its superior end and itsinferior end. The tibial sleeve component 58 may be advanced over thestem adaptor 60 such that the tapered sidewalls forming the bore 68 ofthe tibial sleeve component 58 engage to the tapered outer surface ofthe stem adaptor 60 to taper lock the sleeve component 58 to the stemadaptor 60 to one another. As can be seen in FIG. 1, the inferior end ofthe stem adaptor 60 is configured to receive the stem components 18.Specifically, the inferior end of the stem adaptor 60 has a tapered bore70 formed therein into which a tapered post 28 of one of the stemcomponents 18 may be advanced to taper lock the post 28 (and hence thestem component 18) and the stem adaptor 60 to one another. Accordingly,it should be appreciated that each of the stem components 18 isconfigured to taper fit to any of the femoral component 12, the tibialtray 14, the femoral sleeve component 56, and the stem adaptor 60.

The components of the knee prosthesis assembly 10 that engage thenatural bone, such as the femoral component 12, the tibial tray 14, thestem components 18, the sleeve components 56, 58, and the stem adaptor60 may be constructed with an implant-grade biocompatible metal,although other materials may also be used. Examples of such metalsinclude cobalt, including cobalt alloys such as a cobalt chrome alloy,titanium, including titanium alloys such as a Ti6Al4V alloy, andstainless steel. Such a metallic components may also be coated with asurface treatment, such as hydroxyapatite, to enhance biocompatibility.Moreover, the surfaces of the metallic components that engage thenatural bone may be textured to facilitate securing the components tothe bone. Such surfaces may also be porous coated to promote boneingrowth for permanent fixation.

The bearing 16 may be constructed with a material that allows for smootharticulation between the bearing and the femoral component 12, such as apolymeric material. One such polymeric material is polyethylene such asultrahigh molecular weight polyethylene (UHMWPE).

Referring now to FIGS. 2-3, the femoral component assembly 72 includesthe femoral component 12, a retention device 74, a fastener 76, and astem component 18. As discussed above, the stem component 18 includes atapered post 28 configured to be received in a tapered bore 46 formed inthe stem post 42 of the femoral component 12 to taper lock the taperedpost 28 (and hence the stem component 18) and the femoral component 12to one another.

The stem post 42 of the femoral component 12 includes a passageway 78extending from a distal end 80 to a proximal end 82 along an axis 84. Asshown in FIG. 3, the distal end 80 of the passageway 78 defines anopening 86 from the intercondylar notch 38, and an inner wall 88 extendsinwardly from the opening 86 to define the passageway 78. As shown, thepassageway 78 includes the tapered bore 46 defined at the proximal end82 of the passageway 78, a distal compartment 90 defined at the distalend 80 of the passageway 78, and a threaded passage 92 connecting theproximal tapered bore 46 and the distal compartment 90.

A plurality of internal threads 94 (see FIG. 7) are defined in the innerwall 88 within the threaded passage 92. As described below, the internalthreads 94 are configured to engage external threads 254 of adisassembly tool 208. In that way, the disassembly tool 208 may besecured to the femoral component 12 during a disassembly procedure.

The inner wall 88 of the femoral component 12 includes an annular orcup-shaped connecting surface 96 defining a proximal end 98 of thedistal compartment 90. As shown in FIG. 3, the distal compartment 90 hasone diameter 100, and the threaded passage 92 has another diameter 102.Further, the diameter 100 of the distal compartment 90 is greater thanthe diameter 102 of the threaded passage 92. Accordingly, as shown inFIG. 3, the connecting surface 96 bridges the radial gap between thedistal compartment 90 and the threaded passage 92.

The tapered post 28 of the stem component 18 includes a distal end 104and an opening 106 defined in the distal end 104. An inner wall 108extends inwardly from the opening 106 along the axis 84 to define anaperture 110 in the distal end 104 of the stem component 18. The innerwall 108 of the aperture 110 includes a substantially smooth unthreadedsection 112 and a threaded section 114. As shown in FIG. 3, the threadedsection 114 is defined at a proximal end 116 of the aperture 110 andincludes a plurality of internal threads configured to engagecorresponding threads of the fastener 76. As described in greater detailbelow, the proximal end 116 of the aperture 110 is defined by anengagement surface 217 configured to receive an end 274 of a rodcomponent 214 during a disassembly procedure.

In the illustrative embodiment of FIGS. 2-3, the fastener 76 is a screw.It should be appreciated, however, that the fastener 76 may be anyfastening device or component configured to extend through the femoralcomponent 12 to the stem component 18 through the passageway 78. Thefastener 76 includes a head 118 and an elongated shaft 120. As shown inFIG. 3, the elongated shaft 120 has a threaded section 122 at a base 124of the fastener 76 opposite the head 118 and a substantially smoothunthreaded section 126 between the threaded section 122 and the head118. The threaded section 122 of the fastener 76 includes a plurality ofthreads configured to engage the threaded section 114 of the aperture110 of the stem component 18. The elongated shaft 120 is configured topass through the distal compartment 90 and the threaded passage 92 ofthe femoral component 12.

A driver aperture 128 is defined in an upper surface 130 of the head 118and is shaped to accept a surgical instrument driver 308. For example,the driver aperture 128 may be hex-shaped to accept a hex driver. Ofcourse, the driver aperture 128 may be otherwise shaped to accept asurgical instrument driver head 316 of a different shape. The head 118includes a lower surface 132 opposite the upper surface 132 configuredto engage the connecting surface 96. As such, in some embodiments, thelower surface 132 may have a positive contour corresponding with anegative contour of the connecting surface 96. As shown in FIG. 3, theelongated shaft 120 of the fastener 76 has one diameter 134, and thehead 118 has another diameter 136 that is greater than the diameter 134of the elongated shaft 120.

The retention device 74 of the femoral component assembly 72 isconfigured to hold the fastener 76 in place once it has been secured tothe stem component 18. In the illustrative embodiment of FIGS. 2-3, theretention device 74 is mushroom-shaped with a bore 138 extending alongthe axis 84. The bore 138 is configured to slide over the elongatedshaft 120 of the fastener 76. It should be appreciated that, in someembodiments, the retention device 74 may be configured to slide alongthe unthreaded section 126 of the fastener 76 but not to slide along thethreaded section 122 of the fastener 76.

The retention device 74 includes a cylindrical body 140 with a hood 142extending radially from a distal end 144 of the cylindrical body 140. Insome embodiments, the hood 142 may be a frustoconical body (or curvedversion thereof) extending from the cylindrical body 140. For example,the retention device 74 may be similar in shape to the retention device74 described below in regard to FIG. 19 below with an optionally curvedor rounded proximal end.

As shown in FIG. 3, the retention device 74 is shaped to tightly fit inthe threaded passage 92 of the femoral component 12. In anotherembodiment, the retention device 74 may include only the cylindricalbody 140 without the hood 142. Depending on the particular embodiment,the retention device 74 may also, for example, include a lock washer(e.g., a vinyl or polymeric washer) for use in retaining the fastener76. The retention device 74 may be composed of any material suitable tobe held in place by the threaded passage 92. In the illustrativeembodiment, the retention device 74 may be composed of a polymericmaterial such a high molecular weight polyethylene.

In use, the tapered post 28 of the stem component 18 may be insertedinto the femoral stem post 42 of the femoral component 12. A compressiveload may be applied to the stem component 18 and the femoral component12 to create a taper fit between the stem component 18 and the femoralcomponent 12. In the illustrative embodiment, the taper fit acts as theprimary fastener of the components 12, 18.

After the components 12, 18 are taper locked, the fastener 76 may bealigned with the retention device 74 along the axis 84. The threadedsection 122 of the elongated shaft 120 of the fastener 76 may beinserted through the bore 138 of the retention device 74 to attach thefastener 76 to the retention device 74. The fastener 76 may then bealigned with the passageway 78 of the femoral component 12 along theaxis 84, and the elongated shaft 120 of the fastener 76 may be advancedthrough the passageway 78 into the aperture 110 of the stem component18. A surgical instrument driver may be used to thread the threadedsection 122 of the fastener 76 into the threaded section 114 of theaperture 110 to advance the shaft 120 into contact with the engagementsurface 217 at the end of the aperture 110.

As shown in FIG. 3, the elongated shaft 120 of the fastener 76 has asmaller diameter 134 than the diameter 102 of the threaded passage 92,whereas the head 118 has a greater diameter 136 than the threadedpassage 92. Accordingly, while the elongated shaft 120 is configured topass through the threaded passage 92 and the aperture 110, the head 118is configured to rest in the distal compartment 90 but not pass throughthe threaded passage 92. As the retention device 74 is advanced into thethreaded passage 92 (with the fastener 76) along the axis 84 in a firstdirection 146, the hood 142 of the retention device 74 is deformedtoward a second direction 148 opposite the first direction 146 therebycreating a force sufficient to retain the fastener 76. As shown in FIG.3, the hood 142 is compressed between the head 118 of the fastener 76and the connecting surface 96 of the femoral component 12. In theillustrative embodiment, the fastener 76 and the retention device 74 actas a secondary fastener of the components 12, 18. In that way, the taperfit and the fastener 76 (with the retention device 74) act as dual orredundant attachment measures for the attached components (e.g., thefemoral component 12 and the stem component 18).

Referring now to FIGS. 4-5, a tibial component assembly 150 includes thetibial tray 14, the fastener 76, and the stem component 18. As describedabove, the stem component 18 includes a tapered post 28 configured to bereceived in the tapered bore 26 formed in the tibial stem post 22 of thetibial tray 14 to taper lock the tapered post 28 (and hence the stemcomponent 18) and the tibial tray 14 to one another.

The tibial stem post 22 of the tibial tray 14 includes a passageway 152extending from a proximal end 154 to a distal end 156 along an axis 158.As shown in FIG. 5, the proximal end 154 of the passageway 152 definesan opening 160 in the platform 20, and an inner wall 162 extendsinwardly from the opening 160 to define the passageway 152. As shown,the passageway 152 includes the tapered bore 26 defined at the distalend 156 of the passageway 152, a proximal compartment 164 defined at theproximal end 154 of the passageway 152, and a threaded passage 166connecting the distal tapered bore 26 and the proximal compartment 164.

Similar to the femoral component 12, a plurality of internal threads 168are defined in the inner wall 162 within the threaded passage 166. Asdescribed below, the internal threads 168 are configured to engageexternal threads 254 of a disassembly tool 208. In that way, thedisassembly tool 208 may be secured to the tibial tray 14 during adisassembly procedure. Similar to the inner wall 88 of the femoralcomponent 12, the inner wall 162 of the tibial tray 14 includes anannular or cup-shaped connecting surface 170 defining a distal end 172of the proximal compartment 164. As shown in FIG. 5, the proximalcompartment 164 has a diameter 174 that is greater than the diameter 102of the threaded passage 166. Accordingly, the connecting surface 170bridges the radial gap between the proximal compartment 164 and thethreaded passage 166. In the illustrative embodiment, the proximalcompartment 164 of the tibial tray 14 has the same diameter 100 as thatof the distal compartment 90 of the femoral component 12.

In use, the tapered post 28 of the stem component 18 may be insertedinto the femoral stem post 42 of the tibial tray 14. A compressive loadmay be applied to the stem component 18 and the tibial tray 14 to createa taper fit between the stem component 18 and the tibial tray 14. In theillustrative embodiment, the taper fit acts as the primary fastener ofthe components 14, 18.

After the components 14, 18 are taper locked, the fastener 76 may bealigned with the passageway 152 of the tibial tray 14, and the elongatedshaft 120 of the fastener 76 may advanced through the passageway 152into the aperture 110 of the stem component 18. A surgical instrumentdriver may be used to thread the threaded section 122 of the fastener 76into the threaded section 114 of the aperture 110 to advance the shaft120 into contact with the engagement surface 217 at the end of theaperture 110.

As shown in FIG. 5, the elongated shaft 120 of the fastener 76 has asmaller diameter 134 than the diameter 102 of the threaded passage 166,whereas the head 118 has a greater diameter 136 than the threadedpassage 166. Accordingly, while the elongated shaft 120 is configured topass through the threaded passage 166 and the aperture 110, the head 118is configured to rest in the proximal compartment 164 but not passthrough the threaded passage 166. In the illustrative embodiment, thefastener 76 acts as a secondary fastener of the components 14, 18. Inthat way, the taper fit and the fastener 76 (with the retention device74) act as dual or redundant attachment measures for the attachedcomponents (e.g., the tibial tray 14 and the stem component 18).

It should be appreciated that in other embodiments a retention devicesimilar to the retention device 74 of the femoral component assembly 72may be used to secure the fastener 76 of the tibial component assembly150. In such embodiments, the tibial component assembly 150 may beassembled in a manner similar to the assembly procedures described abovewith regard to assembling the femoral component assembly 72.

Referring now to FIGS. 6-7, the femoral component assembly 72 mayinclude the femoral sleeve component 56 as described above. The femoralsleeve component 56 includes a passageway 184 extending from a distalend 186 to a proximal end 188 along a longitudinal axis 190. As shown inFIG. 7, the passageway 184 includes a tapered bore 180 defined at thedistal end 186 of the passageway 184 and a tapered bore 64 defined atthe proximal end 188 of the passageway 184. The sleeve component 56 alsoincludes a compartment 176 and a threaded passage 178 that connects thebores 64, 180.

As described above, the tapered bore 180 of the femoral sleeve component56 may be taper locked to the outer surface 182 of the femoralcomponent's stem post 42 to lock the sleeve component 56 to the femoralcomponent 12. As shown in FIG. 7, the tapered bore 180 opens into thecompartment 176 of the sleeve component 56. As such, when the sleevecomponent 56 is attached to the femoral component 12, the passageway 78of the femoral component 12 opens into the compartment 176 (and hencethe passageway 184) of the sleeve component 56.

The compartment 176 extends proximally from the tapered bore 180 to thethreaded passage 178. As shown in FIG. 7, the femoral sleeve component56 includes a plurality of internal threads that are defined in an innerwall 192 of the threaded passage 178. The threads, like the threads ofthe femoral component 12 and the tibial tray 14, are configured toengage external threads 254 of the disassembly tool 208 (e.g., during adisassembly procedure), as described in greater detail below.

Similar to the inner wall 88 of the femoral component 12, the inner wall192 of the femoral sleeve component 56 also includes an annular orcup-shaped connecting surface 196 defining a proximal end 198 of thecompartment 176. As shown in FIG. 7, the compartment 176 has a diameter100 that is greater than the diameter 102 of the threaded passage 178.Accordingly, the connecting surface 170 bridges the radial gap betweenthe proximal compartment 164 and the threaded passage 166. In someembodiments, the proximal compartment 164 of the tibial tray 14 has thesame diameter 100 as that of the distal compartment 90 of the femoralcomponent 12.

As described above, the femoral sleeve component 56 is also configuredto receive the stem components 18. Specifically, the femoral sleevecomponent 56 has a tapered bore 64 formed therein into which a taperedpost 28 of one of the stem components 18 may be advanced to taper lockthe post 28 (and hence the stem component 18) and the femoral sleevecomponent 56 to one another. A fastener 76 may be used to secure thefemoral component 12 to the stem component 18, as shown in FIG. 7.

The assembly 72 also includes a retention device 194 configured to holdthe fastener 76 in place once it has been secured to the stem component18. In the illustrative embodiment of FIGS. 2-3, the retention device194 has a cylindrical body 140, and a bore 138 that is configured toslide over the elongated shaft 120 of the fastener 76. It should beappreciated that, in some embodiments, the retention device 194 may beconfigured to slide along the unthreaded section 126 of the fastener 76but not to slide along the threaded section 122 of the fastener 76.

In use, the tapered post 28 of the stem component 18 may be insertedinto the tapered bore 64 defined in the sleeve component 56. Acompressive load may be applied to the stem component 18 and the femoralsleeve component 56 to create a taper fit between the stem component 18and the sleeve component 56. In the illustrative embodiment, the taperfit acts as the primary fastener of the components 18, 56.

After the components 18, 56 are taper locked, the fastener 76 may bealigned with the retention device 194 along the axis 190. The threadedsection 122 of the elongated shaft 120 of the fastener 76 may beinserted through the bore 138 of the retention device 194 to attach thefastener 76 to the retention device 194. The fastener 76 may then bealigned with the passageway 184 of the sleeve component 56 along theaxis 84, and the elongated shaft 120 of the fastener 76 is advancedthrough the passageway 184 into the aperture 110 of the stem component18. A surgical instrument driver may be used to thread the threadedsection 122 of the fastener 76 into the threaded section 114 of theaperture 110 to advance the shaft 120 into contact with the engagementsurface 217 at the end of the aperture 110. In the illustrativeembodiment, the fastener 76 acts as a secondary fastener of thecomponents 18, 56. In that way, the taper fit and the fastener 76 (withthe retention device 194) act as dual or redundant attachment measuresfor the attached components (e.g., the sleeve component 56 and the stemcomponent 18).

After the components 18, 56 are taper locked and secured together withthe fastener 76, the tapered bore 180 of the femoral sleeve component 56may be aligned with the femoral component's stem post 42 and the post 42advanced into the tapered bore 180. A compressive load may be applied tothe femoral component 12 and the femoral sleeve component 56 to create ataper fit between the femoral component 12 and the sleeve component 56to secure the components 12, 56 together.

As shown in FIG. 8, the tibial sleeve component 58 may be used inconjunction with the stem adaptor 60 in the tibial component assembly150. The stem adaptor 60 includes a passageway 200 defined along itslongitudinal axis 202 from its superior end 204 to the tapered bore 70defined at its inferior end 206. The passageway 200 includes a threadedpassage 328 (see FIG. 17) at the stem adaptor's superior end 204 and aconnecting passageway 330 (see FIG. 17) that connects the threadedpassage 328 to the tapered bore 70. An inner wall (not shown) of thethreaded passage 328 defines a plurality of threads 332 (see FIG. 17)configured to engage a disassembly tool 208, as described in greaterdetail below. During assembly, the fastener 76 may be advanced throughthe passageway 200 and engage the threaded section 114 of the aperture110 of the stem component 18 to secure the stem adaptor 60 to the stemcomponent 18. Although not shown, the threaded passage 166 of the tibialtray 14 adjoins the threaded passage 328 of the stem adaptor 60.Accordingly, in other embodiments, a retention device similar toretention devices 74, 194 may be used to secure the fastener 76 and maybe positioned within the threaded passages 328, 166 of the tibial tray14 and/or the stem adaptor 60.

Referring now to FIG. 9, an exploded view of a disassembly tool 208 foruse in disassembling an orthopaedic prosthetic component assembly 10 isshown. The disassembly tool 208 includes a main component 210, a spindlecomponent 212, a rod component 214, a wrench component 216, and a handlecomponent 218. As described below, the main component 210, the rodcomponent 214, and the spindle component 212 may be assembled along alongitudinal axis 220. Each of the components of the disassembly tool208 may be formed from a material capable of withstanding the mechanicalstresses applied to those components as described below. In theillustrative embodiment, the components are formed from a metallicmaterial, such as, for example, a stainless steel or a cobalt chromiumalloy.

The main component 210 includes a housing 222 and an elongated body 224extending inferiorly from the housing 222 along the longitudinal axis220. As shown in FIG. 9A, the housing 222 has an aperture 226 formedtherein extending from an opening 228 at its superior end 230 to anannular surface 232 defined at its inferior end 234. An inner wall 238extends inferiorly from the opening 228 to define the aperture 226. Aplurality of internal threads 240 are defined in the inner wall 238within the aperture 226. In some embodiments, the plurality of internalthreads 240 extend from the opening 228 to the annular surface 232,whereas, in other embodiments, the plurality of internal threads 240 mayextend inferiorly only part of the way to the annular surface 232. Asdescribed below, the internal threads 240 are configured to engage thespindle component 212 of the disassembly tool 208 to force the rodcomponent 214 inferiorly through a bore 244 defined in the elongatedbody 224.

As shown, a diameter 242 of the aperture 226 through the housing 222 isgreater than a diameter 244 of the bore 244 of the elongated body 224 inthe illustrative embodiment. Additionally, an outer surface 246 of thehousing 222 is shaped to match a connection surface or socket 248 of thewrench component 216. That is, a cross section of a portion of the outersurface 246 of the housing 222 taken perpendicular to the longitudinalaxis 220 corresponds to, fits, or otherwise matches a similar crosssection of the socket 248 of the wrench component 216. For example, theouter surface 246 may be hex-shaped to be used with a hex wrench orsquare-shaped to be used with a square-shaped wrench.

As noted above, the elongated body 224 has a bore 244 formed thereinthat extends through its entire length and hence is open to both itssuperior end 236 and its inferior end 250. Additionally an outer surface252 of the elongated body 224 at its inferior end 250 includes aplurality of threads 254. As discussed above, the threads 254 may beused to engage the threaded passages 92, 166, 178 of various orthopaedicprosthetic components during a disassembly procedure. As such, theelongated body 224 has an outer diameter 256 sized to fit through thosethreaded passages 92, 166, 178. For example, depending on the particularorthopaedic prosthetic assembly 10, the elongated body 224 is sized tofit through the distal compartment 90 of the femoral component 12, theproximal compartment 164 of the tibial tray 14, the tapered bore 46 ofthe femoral component's stem post 42, the compartment 176 of the femoralsleeve component 56, and the tapered bore 26 of the tibial tray's stempost 22 to engage the corresponding threaded passage.

Each rod component 214 of the disassembly tool 208 includes a head 258and an elongated shaft 260 extending inferiorly from the head 258 alonga longitudinal axis 262 of the rod component 214. The head 258 is sizedto be received in the aperture 226 of the housing 222 of the maincomponent 210 but not to pass through the elongated body 224 of the maincomponent 210. As described below, in some embodiments, the head 258 issized to fit an aperture 264 defined in an inferior end 266 of thespindle component 212. The elongated shaft 260 is configured to passthrough the elongated body 224 of the main component 210 and has alength 270 greater than the length 272 of the elongated body 224.

In some embodiments, an inferior end 274 of the elongated shaft 260 ofthe rod component 214 may have a diameter 278 less than a diameter 280of a superior end 276 of the elongated shaft 260 or be otherwise shapedto facilitate use of the rod component 214 with other orthopaedicprosthetic components or surgical instruments. For example, the inferiorend 274 of the elongated shaft 260 may be shaped to easily fit throughthe threaded section 114 of the aperture 110 defined in the stemcomponent 18 (e.g., to stably apply force to or “push off” theengagement surface 217 of the stem component 18 with the rod component214 during a disassembly procedure). Alternatively, or additionally, theinferior end 274 of the elongated shaft 260 may be shaped to match thedriver aperture 128 defined in the head 118 of the fastener 76 (e.g., toapply force to the fastener 76 with the rod component 214).

As shown in FIG. 9, the spindle component 212 includes a threaded body282 extending superiorly from an inferior end 266 along the longitudinalaxis 220. The outer surface 284 of the threaded body 282 includes aplurality of exterior threads 286 defined thereon, which are configuredto engage the internal threads 240 of the housing 222 of the maincomponent 210. As described above, in the illustrative embodiment, anaperture 264 is defined in the inferior end 266 of the spindle component212 and may be sized to fit the head 258 of the rod component 214 (e.g.,to stabilize the rod component 214 while applying a force to the rodcomponent 214). However, in other embodiments, an aperture 264 may notbe present.

The spindle component 212 also includes a handle body 288 opposite thethreaded body 282 at a superior end 290 of the spindle component 212.The handle body 288 is configured to receive the handle component 218for use in threading the spindle component 212 into the main component210. As shown in FIG. 9, the handle body 288 may include a plurality ofslots 292 through which an end 294 of the handle component 218 may beinserted during operation of the disassembly tool 208. In anotherembodiment, the handle body 288 may be shaped to otherwise secure thehandle component 218. For example, the handle body 288 may have an outersurface 298 shaped to match the socket 248 another wrench component 216in a manner similar to the outer surface 246 of the housing 222 of themain component 210.

The handle component 218 may include an elongated body 296 with the end294 sized to fit through one or more of the slots 292 defined in thehandle body 288 of the spindle component 212. As discussed above, inanother embodiment, the handle component 218 may have a socket 248 tomatch a corresponding outer surface 298 of the handle body 288 of thespindle component 212 (i.e., the handle component 218 may be anotherwrench component 216). The wrench component 216 includes an elongatedbody 300 with a first end 302 and a second end 304 opposite the firstend 302. As shown, the socket 248 is defined at the first end 302 of theelongated body 300 and configured to match the outer surface 246 of thehousing 222 of the main component 210. Additionally, the second end 304may be shaped to accept a leveraging tool (not shown) or some other toolused during a disassembly procedure. It should be appreciated that thehandle component 218 and the wrench component 216 may be shaped as shownin FIG. 9 or configured in some other way suitable for performing thefunctions described herein.

As shown in FIGS. 10-15, an orthopaedic surgical procedure todisassemble the femoral component assembly 72 using the disassembly tool208. While the procedure is described in reference the assembly 72, theprocedure and the tool 208 may be used to disassemble the otherorthopaedic component assemblies. It should be appreciated that themethods described herein permit a surgeon to disassemble (and assemble)orthopaedic prosthetic component assemblies from the joint line. Inother words, the orthopaedic component assemblies may be disassembledfrom an end of the relevant long bone. For example, in the case of afemoral component assembly 72, the components, the fastener, and theretention device may be accessed from the distal end of the femur suchthat the surgeon may remove the fastener and the retention device anddetach the femoral component without removing the stem component. In thecase of the tibial component assembly 150 without a tibial sleevecomponent 58 or stem adaptor 60, the components and the fastener may beaccessed from the proximal end of the tibia such that the surgeon mayremove the fastener and detach the tibia component without removing thestem component. In the case of a tibial component assembly 150 with atibial sleeve component and a stem adaptor 60, the components and thefastener may be accessed from the proximal end of the tibia such thatthe surgeon may remove the fastener and detach the tibia component andthe stem adaptor 60 without removing the stem component and the tibialsleeve component 58.

Referring now to FIGS. 10-11, the surgeon may remove the fastener 76from the femoral component assembly 72 using a surgical instrumentdriver 308. As discussed above, the fastener 76 may secure the femoralcomponent 12 to the stem component 18 in addition to the taper fitbetween those components. In the illustrative embodiment, the driver 308includes a handle 310 and an elongated shaft 312 extending from thehandle 310. As shown, a driver head 316 is defined at an end 314 of theelongated shaft 312 opposite the handle 310. It should be appreciatedthat the surgeon may use a driver 308 with a head 316 having a shapematching that of the driver aperture 128 of the fastener 76. Forexample, if the fastener 76 is a hex screw, a hex driver may be used toremove the fastener 76 from the femoral component assembly 72. In someembodiments, removing the fastener 76 involves unscrewing it from thestem component 18 and extracting it from the passageway 78 of thefemoral component assembly 72.

Further, as shown in FIG. 11, the surgeon removes the retention device74 using any suitable means. For example, in one embodiment, a screw(e.g., a cork screw) may be driven into the bore 138 of the retentiondevice 74, and the retention device 74 may be removed by force along theaxis 306. Depending on the particular retention device 74 used, anothermethod of removal may be used. For example, in some embodiments, aremoval tool (not shown) may permit nearly effortless removal of theretention device 74. Referring now to FIG. 12, the disassembly tool 208may be assembled as attached to the femoral component 12. To do so, themain component 210 of the disassembly tool 208 is secured to the femoralcomponent 12. For example, in the illustrative embodiment, the elongatedbody 224 of the main component 210 may be threaded into the threadedpassage 92 of the femoral component 12.

The rod component 214 is then selected for use with the femoralcomponent assembly 72. As described herein, the head 258 of the rodcomponent 214 is configured to engage the aperture 264 defined in theinferior end 266 of the spindle component 212, and the inferior end 274of the elongated shaft 260 of the rod component 214 is configured toengage and apply a force against the engagement surface 217 of the stemcomponent 18. Therefore, the length 270 of the elongated shaft 260 ofthe rod component 214 must correspond with the particular orthopaedicprosthetic assembly 10 being disassembled. Specifically, because thelength of the elongated body 224 of the main component 210 is static,the suitable length 270 of the rod component 214 is a function of thedistance between (i) a threaded passageway to which the elongated body224 of the main component 210 is to thread and (ii) the engagementsurface 217 with which the rod component 214 is to engage. Accordingly,it should be appreciated that the rod component 214 chosen to remove aparticular orthopaedic prosthetic component from the assembly 10 may bechosen from a collection 318 of rod components 214, each having a shaft260 with a different length 270 suited to the removal of a particularprosthetic component.

As such, in the illustrative embodiment, the rod component 214 isselected with a length 270 corresponding to a femoral component assembly72 including only a femoral component 12 and a stem component 18. Aftermaking the appropriate selection, the elongated shaft 260 of the rodcomponent 214 is inserted through the aperture 226 defined in thehousing 222 and through the bore 244 in the elongated body 224 of themain component 210. After inserting the rod component 214 through theelongated body 224, the threaded body 282 of the spindle component 212is threaded into the main component 210.

As shown in FIGS. 13-15, the surgeon secures the wrench component 216and the handle component 218 to the main component 210 and the spindlecomponent 212 of the disassembly tool 208, respectively. After securingthose components 210, 212, the surgeon may steady the disassembly tool208 and prevent the disassembly tool 208 from unthreading from a firstorthopaedic prosthetic component (e.g., the femoral component 12) withthe wrench component 216 while rotating the handle component 218relative to the wrench component 216 to further thread the spindlecomponent 212 into the main component 210. Doing so increases a forceapplied to the rod component 214 and, therefore, to the engagementsurface of a second prosthetic component (e.g., the engagement surface217 of the stem component 18). At some point, the force applied to theengagement surface (e.g., the engagement surface 217) may exceed athreshold force (e.g., a breakaway force) required to break a taper fitbetween the first prosthetic component (e.g., the femoral component 12)and the second prosthetic component (e.g., the stem component 18).Accordingly, those prosthetic components may disengage once thethreshold force is reached.

Referring now to FIG. 14, the spindle component 212 has been threadedinto the housing 222 of the main component 210 such that a distance 322between the inferior end 266 of the spindle component 212 and theannular surface 232 of the housing 222 is defined. As shown in FIG. 15,after the spindle component 212 has been further threaded into the maincomponent 210 in a first direction 320, a different distance 324 betweenthe inferior end 266 of the spindle component 212 and the annularsurface 232 of the housing 222 is defined, which is a shorter distance324 than the distance 322. It should be appreciated that as the spindlecomponent 212 is further threaded into the main component 210 in thefirst direction 320, the distance between the inferior end 266 of thespindle component 212 and the annular surface 232 of the housing 222 ofthe main component 210 decreases.

As discussed above, continuing to thread the spindle component 212 intothe main component 210 in the first direction 320 increases the forceapplied to the rod component 214 along the longitudinal axis 306.Accordingly, the force applied to the attached stem component 18increases. The femoral component 12 breaks loose when the force appliedto the stem component 18 reaches the threshold force required to breakthe taper fit between the femoral component 12 and the stem component18. That is, the femoral component 12 is moved in a second direction 326opposite the first direction 320 relative to the stem component 18. Oncethe femoral component 12 has been broken free and removed, the stemcomponent 18 may be removed from the patient using any suitable means(e.g., traditional means). For example, a screw may be threaded into thethreaded section 114 of the aperture 112 of the stem component 18 and a“slap hammer” or other surgical instrument may be used to drive or forcethe stem component 18 from the patient's femur.

As discussed above, in some embodiments a femoral sleeve component 56 isused in conjunction with a stem component 18 to facilitate implantationof the femoral component 12 in the presence of reduced bone quality inthe patient's femur (e.g., the femoral component assembly 72 of FIGS.6-7). In such an embodiment, the disassembly tool 208 (with theappropriate rod component 214) may be assembled and secured to thethreaded passage 92 of the femoral component 12. As discussed above, theinferior end 274 of the elongated shaft 260 of the rod component 214(i.e., the end 274 configured to protrude from the elongated body 224 ofthe disassembly tool 208) may be shaped to fit or otherwise contact thedriver aperture 128 defined in the head 118 of the fastener 76. As such,a force is applied to the head 118 of the fastener 76 as the spindlecomponent 212 is threaded into the main component 210 of the disassemblytool 208 rather than the force being applied directly to the stemcomponent 18.

Once the femoral component 12 breaks loose from the femoral sleevecomponent 56, the femoral component 12 may be removed from the assembly(e.g., using a slap hammer). Thereafter, the fastener 76 and theretention device 74 may be removed from the femoral sleeve component 56and stem component 18 as described above. After the fastener 76 andretention device 74 are removed, the disassembly tool 208 (with anappropriate rod component 214) may be secured to the threaded passage178 of the femoral sleeve component 56. It should be appreciated thatthe rod component 214 used for removing the femoral component 12 mayhave a different length 270 than the rod component 214 used to removethe femoral sleeve component 56. The femoral sleeve component 56 isloosened from the stem component 18 using the disassembly tool 208 andthe methods described herein. Additionally, the femoral sleeve component56 and the stem component 18 may be removed thereafter using suitablemeans (e.g., using a slap hammer).

As shown in FIGS. 16-18, disassembly of a tibial component assembly 150includes the use of the disassembly tool 208. The tibial componentassembly 150 shown in FIGS. 16-18 includes the tibial tray 14, the stemcomponent 18, the tibial sleeve component 58, the stem adaptor 60, andoptionally the fastener 76. As shown in FIG. 16, the tibial tray 14 maybe removed from the tibial component assembly 150 using any suitablemeans (e.g., traditional means). Accordingly, if the fastener 76 isused, it may be removed in addition to the tibial tray 14 as discussedabove. After removing the tibial tray 14, the tibial sleeve component58, the stem adaptor 60, and the stem component 18 of the tibialcomponent assembly 150 remain assembled.

As shown in FIGS. 17-18, the disassembly tool 208 is assembled andsecured to the threaded passage 328 of the stem adaptor 60.Specifically, the elongated body 224 of the main component 210 isthreaded into the threaded passage 328 of the stem adaptor 60.Additionally, a rod component 214 is chosen with a length 270corresponding to a tibial component assembly 150 including only the stemadaptor 60 and the stem component 18 and advanced through the bore 244of the elongated body 224 to engage the engagement surface 217 of thestem component 18. Thereafter, the surgeon threads the spindle component212 into the main component 210 of the disassembly tool and secures thewrench component 216 and the handle component 218.

Referring now to FIG. 17, the spindle component 212 has been threadedinto the housing 222 of the main component 210 such that a distance 336between the inferior end 266 of the spindle component 212 and theannular surface 232 of the housing 222 is defined. As shown in FIG. 18,after the spindle component 212 has been further threaded into the maincomponent 210 in a first direction 334, a different distance 338 betweenthe inferior end 266 of the spindle component 212 and the annularsurface 232 of the housing 222 is defined, which is a shorter distance338 than the distance 336. As described above in reference to FIGS.14-15, as the spindle component 212 is further threaded into the maincomponent 210, the distance between the inferior end 266 of the spindlecomponent 212 and the annular surface 232 of the housing 222 of the maincomponent 210 decreases, and the force applied to the rod component 214(and therefore to the stem component 18) along a longitudinal axis 342increases.

The stem adaptor 60 breaks loose when the force applied to the stemcomponent 18 reaches the threshold force required to break the taper fitbetween the stem adaptor 60 and the stem component 18. That is, the stemadaptor 60 is moved in a second direction 340 opposite the firstdirection 334 relative to the stem component 18. Once the stem adaptor60 has been broken free and removed, the stem component 18 and thetibial sleeve component 58 may be remove from the patient using anysuitable means (e.g., traditional means). For example, a screw may bethreaded into the threaded aperture 110 of the stem component 18 and a“slap hammer” or other surgical instrument may be used to drive or forcethe stem component 18 from the patient's tibia. In some cases, the forceassociated with extracting the stem component 18 loosens the tibialsleeve component 58 as well.

As discussed above, in some embodiments a tibial component assembly 150includes only the tibial tray 14, the stem component 18, and thefastener 76. The methods described herein may also be used todisassemble such an assembly. Specifically, the fastener 76 may beremoved using, for example, the driver 308 as described above. After arod component 214 having a suitable length for the assembly 150 ischosen, the disassembly tool 208 is secured to the threaded passage 166of the tibial tray 14, assembled, and operated as discussed above toloosen the tibial tray 14 from the stem component 18. The stem component18 may then be removed (e.g., using a slap hammer or other removaltool).

Referring now to FIGS. 19-21, as discussed above, other retentiondevices 74 may be used in other embodiments to secure the fastener 76(i.e., prevent the fastener 76 from “backing out”). Depending on theembodiment, use of other retention devices 74 may require minormodification to one or more components of the orthopaedic prostheticassemblies 10 described above (e.g., to the distal compartment 90 of thefemoral component 12).

As shown in FIG. 19, the retention device 74 may be mushroom-shaped andconfigured to fit in a passageway 344 outside a threaded passage 346. Inthe case of retaining a femoral component 12 to a stem component 18, theretention device 74 may be configured to rest in the distal compartment90 of the stem post 42 of the femoral component 12. The mushroom shapedretention device 74 has radial symmetry about an axis 348. Specifically,the retention device 74 includes an annular cylinder 350 with a radiallyextending frustoconical body 352 extending from the annular cylinder 350at a proximal end 354 of the retention device 74. That is, a crosssection taken along the radial axis 348 of the retention device 74 showsa triangular section 356 at the proximal end 354 of the retention device74 with one base 358 of the triangle 356 being coincident with theannular cylinder 350 and the other base 360 perpendicular to the annularcylinder 350 and offset from the proximal end 354 of the retentiondevice 74 by the length of the base 358.

Accordingly, in an embodiment using such a retention device 74, thepassageway 344 may include a groove 362 sized to fit the frustoconicalbody 352 of the retention device 74 in such a way as to hold theretention device 74 in place. In some embodiments, a bore 138 definedthrough the axis 348 of the retention device 74 may be used, forexample, by a removal tool (not shown) to remove the retention device74. It should be appreciated that the retention device 74 is similar tothe retention device 74 discussed above with regard to FIGS. 2-3 but isinserted into the passageway 344 in an opposite direction and not placedin the threaded passage 346. Accordingly, during disassembly, theretention device 74 may be removed prior to removing the fastener 76,thereby affording join line access to the fastener 76. Additionally, theretention device 74 of FIG. 19 may have a larger radius 368 than that ofthe retention device 74 discussed above vis-à-vis FIGS. 2-3.

As shown in FIG. 20-21, another retention device 74 may be used tosecure the fastener 76 and may similarly be configured to rest in thepassageway 344. As shown, the retention device 74 is generally radiallysymmetric about an axis 382 and includes an annular cylinder 374 with afrustoconical body 376 extending from a distal end 378 of the retentiondevice 74 and grooves 370 along the outer surface 372 of the retentiondevice 74 for use by a removal tool (not shown). Additionally, in someembodiments, the proximal end 380 of the retention device 74 may berounded. As in the case of the retention device 74 of FIG. 19, in anembodiment using such a retention device 74, the passageway 344 mayinclude a groove 384 sized to fit the frustoconical body 376 of theretention device 74 in such a way as to hold the retention device 74 inplace.

In other embodiments, another retention device 74 may be used to securethe fastener 76 within the passageway 344 or the threaded passage 346.For example, in some embodiments, the passageway 344 defines a grooveinto which a retention device 74 may be inserted, similar to the groove384 discussed above. The groove may be shaped to fit, for example, ano-ring sized to prevent the fastener 74 from moving beyond the groove.In some embodiments, the o-ring may be helical, whereas in otherembodiments, the o-ring may be a substantially annular body or anannular cylinder. In yet another embodiment, the retention device 74 mayinclude a c-clip shaped to fit into the groove. Alternatively, theretention device 74 may include a bore through which the fastener 76 isinserted, and the retention device 74 may be received in the threadedpassage 346 rather than in the passageway 344. For example, theretention device 74 may include or otherwise constitute a countersunkwasher, an external tooth washer, an external tooth serrated washer, oran angled washer configured to be received in the threaded passage 346.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the apparatus, system, and method describedherein. It will be noted that alternative embodiments of the apparatus,system, and method of the present disclosure may not include all of thefeatures described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the apparatus, system, andmethod that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the presentdisclosure.

1. A method for joint line assembly of an orthopaedic prosthesisassembly, the method comprising: inserting a tapered post of a firstprosthetic component into a tapered bore of a second prostheticcomponent along a longitudinal axis to secure the first prostheticcomponent to the second prosthetic component, advancing, along thelongitudinal axis, a shaft of a fastener through a threaded passagewaydefined in the second prosthetic component and into the first prostheticcomponent, the threaded passageway having a greater diameter than adiameter of the shaft, and threading an end of the shaft into a threadedaperture defined in the first prosthetic component.
 2. The method ofclaim 1, wherein the first prosthetic component is a stem component andthe second prosthetic component is a femoral component including (i) abearing surface having a medial condyle surface and a lateral condylesurface, (ii) a backside surface opposite the bearing surface, and (iii)a stem post extending superiorly away from the backside surface, thetapered bore being defined in the stem post.
 3. The method of claim 1,wherein the second prosthetic component is a femoral sleeve componentincluding a plurality of step surfaces and the first prostheticcomponent is a stem component including an elongated body extending fromthe tapered post.
 4. The method of claim 1, further comprising insertinga tapered stem post of a femoral component into a second tapered bore ofthe second prosthetic component to secure the femoral component to thesecond prosthetic component, the femoral component including (i) abearing surface having a medial condyle surface and a lateral condylesurface, (ii) a backside surface opposite the bearing surface, and (iii)the tapered stem post extending superiorly away from the backsidesurface, wherein the first second prosthetic component is a femoralsleeve component including a plurality of step surfaces and the firstprosthetic component is a stem component including an elongated bodyextending from the tapered post.
 5. The method of claim 1, wherein thefirst prosthetic component is a stem component including an elongatedbody extending from the tapered post and the second prosthetic componentis a tibial tray including (i) a bearing surface configured to contact abearing (ii) a backside surface opposite the bearing surface, and (iii)a stem post extending inferiorly away from the backside surface, thetapered bore being defined in the stem post.
 6. The method of claim 1,wherein inserting the tapered post of the first prosthetic componentinto the tapered bore of the second prosthetic component comprisessecuring the first prosthetic component to the second prostheticcomponent by a taper fit.
 7. The method of claim 6, wherein the firstprosthetic component is secured to the second prosthetic component byonly the taper fit and the fastener.
 8. The method of claim 1, furthercomprising advancing a retention device through the second prostheticcomponent along the longitudinal axis to engage the threaded passagewaydefined in the second prosthetic component.
 9. A method for joint lineassembly of an orthopaedic prosthesis assembly, the method comprising:inserting a tapered post of a stem component into a first tapered boreof a femoral sleeve component along a longitudinal axis to secure thestem component to the femoral sleeve component, the first tapered borelocated at a first end of the femoral sleeve component, advancing alongthe longitudinal axis a shaft of a fastener through a threadedpassageway defined in the femoral sleeve component and into the stemcomponent, the shaft having a first diameter and the threaded passagewayhaving a second diameter greater than the first diameter, threading theend of the fastener into a threaded aperture defined in the stemcomponent, and inserting a tapered stem post of a femoral component intoa second tapered bore of the femoral sleeve component along thelongitudinal axis to secure the femoral component to the femoral sleevecomponent, the second tapered bore located at a second end of thefemoral sleeve component opposite the first end along the longitudinalaxis.
 10. The method of claim 9, wherein the stem component and thefemoral sleeve component are secured by only a taper fit between thestem component and the femoral component and the fastener.
 11. Themethod of claim 9, further comprising inserting the stem component intoa femur of a patient.
 12. The method of claim 9, wherein advancing theshaft of a fastener comprises advancing a head of the fastener through adistal passageway defined in the femoral sleeve component distal to thethreaded passageway, the head having a third diameter greater than thesecond diameter.
 13. The method of claim 9, wherein advancing the end ofthe fastener through the threaded passageway comprises advancing the endof the fastener through the threaded passageway defined in the femoralsleeve component prior to inserting the tapered stem post of the femoralcomponent into the second tapered bore of the femoral sleeve component.14. The method of claim 9, further comprising advancing a retentiondevice through the femoral sleeve component along the longitudinal axisto engage the threaded passageway defined in the femoral sleevecomponent.
 15. An orthopaedic prosthesis assembly, comprising: a firstprosthetic component including (i) an outer surface, (i) a surfacepositioned opposite the outer surface that is configured to contact abone of a patient, and (iii) a stem post extending from the surfacealong an axis, a second prosthetic component including (i) a first endsecured to the stem post, (ii) a second end opposite the first end, and(iii) a tapered bore defined in the second end, and a third prostheticcomponent including a tapered post received in the tapered bore of thesecond prosthetic component, the tapered post having a bore formedtherein extending along the axis, wherein (i) a passageway is defined inthe orthopaedic knee prosthesis assembly along the axis from the outersurface of the first prosthetic component to an end of the bore of thethird prosthetic component, and (ii) a fastener extends along the axisis secured to the second prosthetic component and the third prostheticcomponent.
 16. The orthopaedic prosthesis assembly of claim 15, whereineach of the first prosthetic component, the second prosthetic component,and the third prosthetic component is devoid of an opening transverse tothe axis.
 17. The orthopaedic prosthesis assembly of claim 15, whereinthe second prosthetic component is a femoral sleeve component includinga plurality of step surfaces and the third prosthetic component is astem component including an elongated body extending from the taperedpost.
 18. The orthopaedic prosthesis assembly of claim 17, wherein thefirst prosthetic component is a femoral component including (i) theouter surface having a medial condyle surface and a lateral condylesurface, (ii) a backside surface opposite the outer surface, and (iii) atapered stem post extending superiorly away from the backside surface.19. The orthopaedic prosthesis assembly of claim 15, wherein the firstprosthetic component is a tibial tray including (i) the outer surface,the outer surface being configured to contact a bearing (ii) a backsidesurface opposite the outer surface, and (iii) the stem post extendinginferiorly away from the backside surface, wherein the second prostheticcomponent is a tibial stem adaptor including a second tapered postdefined at the first end, and wherein the third prosthetic component isa stem component having an elongated body extending from the taperedpost.